Cement interdigitation and bone-cement interface after augmenting fractured vertebrae: A cadaveric study

Aseptic loosening caused by mechanical factors is a recognized failure mode for tibial components of knee prostheses. This parametric study investigated the effects of prosthesis fixation design changes, which included the presence, length and diameter of a central stem, the use of fixation pegs beneath the tray, all-polyethylene versus metal-backed tray, prosthesis material stiffness, and cement mantle thickness. The cancellous bone compressive stresses and bone–cement interfacial shear stresses, plus the reduction of strain energy density in the epiphyseal cancellous bone, an indication of the likelihood of component loosening, and bone resorption secondary to stress shielding, were examined. Design features such as longer stems reduced bone and bone–cement interfacial stresses thus the risk of loosening is potentially minimized, but at the expense of an increased tendency for bone resorption. The conflicting trend suggested that bone quality and fixation stability have to be considered mutually for the optimization of prosthesis designs. By comparing the bone stresses and bone–cement shear stresses to reported fatigue strength, it was noted that fatigue of both the cancellous bone and bone–cement interface could be the driving factor for long-term aseptic loosening for metal-backed tibial trays.

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A Crack Model of a Bone Cement Interface

Journal of Biomechanical Engineering ◽

10.1115/1.3138488 ◽

1984 ◽

Vol 106 (3) ◽

pp. 235-243 ◽

Cited By ~ 9

Author(s):

J. P. Clech ◽

L. M. Keer ◽

J. L. Lewis

Keyword(s):

Bone Cement ◽

Cohesive Zone ◽

Edge Crack ◽

Crack Problem ◽

Bimaterial Interface ◽

Fracture Mechanisms ◽

Homogeneous Material ◽

Crack Model ◽

Cement Interface ◽

Crack Faces

This paper is concerned with the fracture mechanics of a bone-cement interface that includes a cohesive zone effect on the crack faces. This accounts for the experimentally observed strengthening mechanism due to the mechanical interlock between the crack faces. Edge crack models are developed where the cohesive zone is simulated by a continuous or a discrete distribution of linear or nonlinear springs. It is shown that the solution obtained by assuming a homogeneous material is fairly close to the exact solution for the bimaterial interface edge crack problem. On the basis of that approximation, the analysis is conducted for the problem of two interacting edge cracks, one at the interface, and the other one in the cement. The small crack that was observed to initiate in the cement, close to the bone-cement interface, does not affect much the mode I stress-intensity factor at the tip of the interface crack. However it may grow, leading to a catastrophic breakdown of the cement. The analysis and following discussion point out an interdependency between bone-cement interface strength and cement strength not previously appreciated. The suggested crack models provide a framework for quantifying the fracture mechanisms at the bone-cement interface.

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A method for bone-cement interface thermometry: An in vitro comparison between low temperature curing cement Palavit® and Surgical Simplex® P

Acta Orthopaedica Scandinavica ◽

10.3109/17453679108994493 ◽

1991 ◽

Vol 62 (6) ◽

pp. 546-548 ◽

Cited By ~ 18

Author(s):

Søren Harving ◽

Kjeld Søballe ◽

Cody Bünger

Keyword(s):

Low Temperature ◽

Bone Cement ◽

Cement Interface ◽

In Vitro Comparison ◽

Curing Cement

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Axisymmetric Finite Element Analysis of a Debonded Total Hip Stem With an Unsupported Distal Tip

Journal of Biomechanical Engineering ◽

10.1115/1.2796023 ◽

1996 ◽

Vol 118 (3) ◽

pp. 399-404 ◽

Cited By ~ 12

Author(s):

T. L Norman ◽

V. C. Saligrama ◽

K. T. Hustosky ◽

T. A. Gruen ◽

J. D. Blaha

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Stress Relaxation ◽

Bone Cement ◽

Cement Mantle ◽

Load Level ◽

Interface Conditions ◽

Element Analysis ◽

Cement Interface ◽

Total Hip

A tapered femoral total hip stem with a debonded stem-cement interface and an unsupported distal tip subjected to constant axial load was evaluated using two-dimensional (2D) axisymmetric finite element analysis. The analysis was performed to test if the mechanical condition suggest that a “taper-lock” with a debonded viscoelastic bone cement might be an alternative approach to cement fixation of stem type cemented hip prosthesis. Effect of stem-cement interface conditions (bonded, debonded with and without friction) and viscoelastic response (creep and relaxation) of acrylic bone cement on cement mantle stresses and axial displacement of the stem was also investigated. Stem debonding with friction increased maximum cement von Mises stress by approximately 50 percent when compared to the bonded stem. Of the stress components in the cement mantle, radial stresses were compressive and hoop stresses were tensile and were indicative of mechanical taper-lock. Cement mantle stress, creep and stress relaxation and stem displacement increased with increasing load level and with decreasing stem-cement interface friction. Stress relaxation occur predominately in tensile hoop stress and decreased from 1 to 46 percent over the conditions considered. Stem displacement due to cement mantle creep ranged from 614 μm to 1.3 μm in 24 hours depending upon interface conditions and load level.

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